import datetime
import os
import sqlite3
from pathlib import Path
from sqlite3 import Connection

CREATE_MIGRATIONS_TABLE = """
CREATE TABLE IF NOT EXISTS migrations (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    file TEXT,
    created_at TEXT
);
"""

def init_db():
    conn = sqlite3.connect("db.sqlite")

    # Create migration table, if not exists yet
    conn.execute(CREATE_MIGRATIONS_TABLE)
    conn.commit()

def create_migration(conn: Connection, migration: str):
    conn.execute(f"""
    INSERT INTO migrations (file, created_at) VALUES ("{migration}", "{datetime.datetime.now()}");
    """)

"""
Returns True, if the migration has already been migrates once.
"""
def check_migration(conn: Connection, migration: str):
    res = conn.cursor().execute(f"""
    SELECT EXISTS(SELECT file FROM migrations WHERE file = "{migration}");
    """)
    return res.fetchone()[0] == 1

if __name__ == "__main__":
    # Init DB with migrations table
    init_db()

    migrations_path = os.path.join(os.path.dirname(__file__), 'migrations')

    try:
        if not os.path.isdir(migrations_path):
            raise FileNotFoundError

        conn = sqlite3.connect("db.sqlite")
        for file in sorted(os.listdir(migrations_path)):
            if not file.endswith('.sql'):
                continue
            with open(os.path.join(os.path.dirname(__file__), 'migrations', file)) as migration:
                migration_name = Path(file).stem

                if check_migration(conn, migration_name):
                    continue

                print(f"Migrating {migration_name}...")
                create_migration(conn, migration_name)
                conn.execute(migration.read())
                print(f"Migrated {migration_name}\n")

        conn.commit()
    except FileNotFoundError:
        print("migrations/ Directive could not be found within the db directory, contained in the project main directory.")